The Virology Laboratory (VL) shall serve as the central laboratory for hepatitis C virus testing as well as a central repository for serum and liver tissue from patients participating in the study. The VL shall provide expert advice regarding virological testing and how results can provide further insights into the natural history of hepatitis C and the effects of interferon therapy. The VL shall work actively with the Steering Committee of the Trial to apply new molecular approaches to the study of patients with chronic hepatitis C participating in this Trial. The VL shall thus provide uniform, efficient and high quality virologicial testing and interpretation in support of the Trial.